Video Transcript
According to the modern atomic theory, which of the following is correct? (A) The electron behaves as a material particle only. (B) The electron behaves as a wave only. (C) The electron behaves both as a material particle and as a wave. (D) The electron moves in a fixed circular orbit round the nucleus.
Throughout the years, the models and theories describing the atom have changed quite a bit as new experimental evidence has emerged. Perhaps the most surprising change to atomic theory happened at the beginning of the 20th century when scientists discovered that small particles like electrons have both particle- and wavelike properties. Electrons behave as a particle because they have a mass. Electrons also behave as particles because when they collide, they’ll bounce off each other. Electrons behave like waves because they produce an interference pattern in the double-slit experiment the same way light does, which travels as a wave.
Previously, the electron was described as a particle only, moving around the nucleus in a fixed circular orbit. The discovery of the wavelike properties of the electron meant that this model of the atom needed updating, which was done with the help of a new branch of physics called quantum mechanics. According to quantum mechanics, which modern atomic theory is largely based on, the electron is spread out in space around the nucleus like a cloud. The shape of this electron cloud is described by a mathematical function called an atomic orbital. The atomic orbital helps us describe the most likely location of an electron in an atom.
So “According to modern atomic theory, which of the following is correct?” That’s answer choice (C). The electron behaves both as a material particle and as a wave.
